For the design of disk type magnetic storage systems it is useful to determine the force applied to a magnetic head and its mounting at various relative speeds, including high speed rotation of the disk, when the head is normally spaced slightly from the disk and "flies" over the disk surface.
Various techniques have been proposed heretofore for measuring static and dynamic friction. Typical publications showing such systems include C. E. Carpenter U.S. Pat. No. 1,772,415; F.D. Long, U.S. Pat. No. 3,020,744; and Japanese Patent Application 53-61515, published Dec. 1, 1979. These patents disclose variable angle planes to determine static friction, and the Japanese disclosure indicates the use of an accelerometer to provide a more complete picture of the movement of an object on a slanted plane. However, none of these systems discloses a method or apparatus for determining the drag or frictional force between two objects which are moving relative to one another under constant or stable dynamic conditions.
Accordingly, a principal object of the present invention is to provide a simple and inexpensive technique for determining the force or drag between a magnetic head and a rotating magnetic disk, or other similar relatively movable objects.